Present door closer incorporate pneumatic or hydraulic means to control the momentum of the door.
Pneumatically controlled door closers have a limited life due to a lack of continuous or repeated lubrication to cylinders and piston seals.
Hydraulically controlled door closers are well lubricated, last longer than the pneumatically controlled door closers, however, when the seals wear out, the piston soon jams within the cylinder and the door is totally inoperable and, if force is applied to the door, the door may be unhinged, causing substantial damage to the door and the door jamb. In addition, the leaking hydraulic fluid damages the surrounding door and floor finishes and, in case of fire, the hydraulically controlled door closers may explode thus is adding to the peril.
All presently available door closers require a substantial force to operate them. The very young, elderly or disabled persons may not be able to operate doors fitted with these door closers.